With motor vehicles, such as commercial vehicles, it is usual to attach attachment parts, such as for example mufflers, exhaust gas cleaning devices, vehicle batteries, fuel tank and stowage containers to a carrying part of the vehicle suitable for this purpose. Attachment parts of this type are typically mounted to a carrying frame or side member of the vehicle. For the mounting, it would be desirable that the fastening devices be able to render the attaching of the attachment parts as simple as possible.